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- OPEN ACCESSClimate change threatens marine ecosystems with known effects on marine life, including changes in metabolic rates, survival, and community structure. Based on a structured literature review, we developed a conceptual “pathways of effects” model that summarizes how three stressors associated with climate change (warming, acidification, and storms) affect functional species groups on the West Coast of Vancouver Island, Canada. We identified 155 distinct pathways from the three stressors through 12 categories of biological effects ranging from changes in the biochemistry of individual organisms to effects on community composition. Most species groups were affected by several climate stressors and via many pathways, although individual studies generally considered only a small fraction of relevant pathways. These effects depended on the species of interest and geographical location, highlighting the importance of local research. Climate change stressors exert complex, sometimes contradictory effects that vary across ecological scales. For example, some stressors that adversely affected a species in laboratory studies appeared beneficial in community-scale field studies. Pathways of effects models are helpful tools to summarize scientific studies across ecological scales. Compiling them in standardized databases would allow researchers and practitioners to search across species and regions to better support ecosystem-based management and environmental impact assessment.
- OPEN ACCESS
- Amanda L. Loder,
- Adam Gillespie,
- Omid Haeri Ardakani,
- Cecilia Cordero Oviedo, and
- Sarah A. Finkelstein
Reported rates of soil organic carbon (SOC) accumulation in wetlands are markedly higher over recent versus longer timescales, caused by SOC losses through decomposition, paleoenvironmental changes, and recent increases in sedimentation or biomass production. Explaining changes in SOC sequestration rates and determining the time horizon over which high rates are sustained are both critical for accurately measuring the potential for wetland conservation as a natural climate solution. Here, we present analyses on a 4-m core from a riverine-influenced marsh in Big Creek watershed, southern Ontario, to track changes in SOC accumulation regimes. Since wetland initiation ∼5700 years ago, mean long-term (pre-industrial) rates of SOC accumulation were 24 g C m−2 year−1, and recent rates up to four times higher. We demonstrate that elevated recent rates of SOC accumulation are largely explained by more labile carbon in surficial soils, and are sustained for less than a century before transitioning to slower burial rates of predominantly recalcitrant organic matter. However, there are exceptions to this trend, such as when labile SOC was buried intermittently during Holocene Lake Erie highstands. Our research underscores the importance of organic matter type and hydroclimatic context in predicting long-term potential for marsh soils to stabilize atmospheric carbon. - OPEN ACCESSWalleye/ogaa (Sander vitreus (Mitchill)) (hereafter, walleye; ogaa = Ojibwe translation) populations have historically supported important multi-use, harvest-oriented fisheries. Despite intensive management, walleye populations have declined in the midwestern United States raising concerns about the sustainability of the species. Numerous factors have been implicated in walleye population declines, including climate change, habitat loss, invasive species, species-interactions, production overharvest (i.e., harvest consistently exceeding annual production), and changing angler behaviors. These factors have negatively influenced natural recruitment and contributed to depensatory recruitment dynamics. I provide a review and perspective suggesting that the current trajectory of walleye populations is at or nearing an ecological tipping point. Although fish populations are often considered compensatory (i.e., negatively density-dependent), current walleye populations appear prone to depensation (i.e., positive density dependence). My review and perspective suggest that a compensatory management perspective for walleye is misaligned. A change in management towards a depensatory resource focus using ecosystem-based fisheries management and the recognition of walleye fisheries as social–ecological systems is needed for conservation. If compensatory management ensues, walleye persistence will likely be further threatened because many drivers of change are outside of managerial control, and those commonly used within managerial control have seemingly been ineffective for sustaining or rehabilitating naturally reproducing walleye populations.
- OPEN ACCESS
- Graham Epstein,
- Susanna D. Fuller,
- Sophia C. Johannessen,
- Emily M. Rubidge,
- Melissa Turner, and
- Julia K. Baum
Marine conserved areas (MCAs) can provide a range of ecological and socio-economic benefits, including climate change mitigation from the protection and enhancement of natural carbon storage. Canada's MCA network is expanding to encompass 30% of its Exclusive Economic Zone by 2030. At present, the network aims to integrate climate change mitigation by protecting coastal vegetated blue carbon ecosystems (saltmarsh, seagrass, kelp). Here, we argue that incorporating unvegetated seabed sediments could bring similar benefits. Seabed sediments can store and/or accumulate high densities of organic carbon, and due to their large spatial extent, contain carbon stores orders of magnitude larger than coastal vegetated habitats. We estimate that currently designated MCAs encompass only 10.8% of Canada's seabed sediment organic carbon stocks on the continental margin, and only 13.4% of areas with high carbon densities. Proposed MCAs would cover an additional 8.8% and 6.1% of total stocks and high carbon areas, respectively. We identify an additional set of high-priority seabed areas for future research and potential protection, ranking their importance based on carbon stocks, proxies for lability, and ecological/biological significance. The incorporation of seabed sediments into MCA networks could support climate change mitigation by preventing future releases of stored carbon. - OPEN ACCESS
- Wesley J. Glisson,
- Michelle Nault,
- Chris Jurek,
- Eric Fischer,
- Keegan Lund,
- Kylie Bloodsworth Cattoor,
- April Londo,
- Nicole Kovar,
- Emelia Hauck-Jacobs,
- Rod Egdell,
- Steve McComas,
- Eric Fieldseth, and
- Daniel J. Larkin
Nitellopsis obtusa (starry stonewort) is an invasive macroalga subject to substantial control efforts in the Midwestern United States; however, there has not been systematic evaluation of treatment effectiveness. We synthesized management approaches and outcomes using monitoring performed over a decade-long period across 38 lakes in Indiana, Wisconsin, and Minnesota. Copper-based algaecide treatments were the primary means of control, followed by physical removal methods or combination treatments. Control efforts and associated monitoring data varied by spatial scale, as did surveyors’ N. obtusa sampling methods. At the largest (whole-lake) scale, we found no evidence that algaecide treatments were slowing expansion or reducing abundance of N. obtusa within infested lakes. At smaller, within-lake scales, we found that algaecide and physical treatments could reduce N. obtusa frequency and biomass, but outcomes were highly variable. At the smallest scales, hand pulling was an effective containment strategy for small, localized populations that were detected early. These results highlight the need to set realistic goals for N. obtusa control and develop improved management techniques. There were also critical gaps in monitoring that limited our ability to evaluate treatment effectiveness. In particular, increased monitoring of unmanaged reference lakes and untreated areas within managed lakes is needed. - OPEN ACCESS
- Breanna Bishop,
- Emmelie Paquette,
- Natalie Carter,
- Gita Ljubicic,
- Eric C.J. Oliver, and
- Claudio Aporta
Environmental indicators are naturally occurring variables, conditions, and events that are used to assess and monitor environmental conditions and change. Inuit throughout Inuit Nunaat (Inuit circumpolar homelands) observe and experience environmental indicators as they travel year-round for harvesting and other cultural practices. Inuit draw on their observations of current conditions and their knowledge of weather, water, ice, and climate (WWIC) indicators, when seeking to predict and understand conditions that impact safe travel. This scoping review documents the types and diversity of WWIC indicators articulated in peer-reviewed and grey literature as being used by Inuit in Canada, Alaska, and Greenland to assess travel safety. Two reviewers independently screened 512 studies using pre-determined eligibility criteria and 123 studies were included for review. A total of 163 unique WWIC indicators were used across 85 communities in Canada, Alaska, and Greenland. Indicators reflect a broad range of ways that Inuit experience their environment, through sight, feel, and sound. Indicators can be considered as causal, conditional, or predictive (or a combination thereof), where knowledge of the interactions among various indicators is especially important to support safe travel. Identified gaps and future research directions included assessing key indicators to better target development of locally relevant research and information services. - OPEN ACCESS
- Stephanie Graves,
- Shao-Min Chen,
- Rachel McNamee,
- Tazi H. Rodrigues,
- Brian Hayden,
- Chelsea M. Rochman,
- Jennifer F. Provencher,
- Michael D. Rennie,
- Daniel Layton-Matthews,
- Matthew Leybourne,
- Owen A. Sherwood, and
- Diane M. Orihel
Microplastics degrade slowly over time, leaching carbon (C) that could be subsequently incorporated into aquatic food webs. Current estimates of microplastic degradation vary, and little is known about microplastic-derived C fate under natural environmental conditions. To investigate whether microplastics leach C that is subsequently incorporated into aquatic food webs, we added isotopically enriched microplastics to Lake 378 at the Experimental Lakes Area in Ontario, Canada. In an ∼1100 L limnocorral (in situ open-bottom enclosure), we added 99% 13C-labelled polystyrene (8–216 µm in longest dimension) at a nominal concentration of 3268 particles/L. A second limnocorral without microplastics served as a negative control. Monthly measurements of δ13C-DIC and δ13C-DOC in filtered water revealed no detectable leaching of 13C from the plastic. Compound-specific isotope analysis of δ13C in amino acids of bulk plankton and periphyton revealed a slight (0.5‰) enrichment in 13C, within the range of natural variability for these organisms. Under the natural conditions of temperate oligotrophic lakes, degradation of microplastics is likely a very slow process that was not possible to detect in this 4-month experiment. Future studies should focus on assessing degradation of microplastics under realistic field scenarios to improve estimates of degradation pathways and associated time scales. - OPEN ACCESS
- Kara L. Webster,
- Maria Strack,
- Nicole Balliston,
- Marissa A. Davies,
- E. Kathryn Hettinga,
- Miranda Hunter,
- Kimberly Kleinke,
- Megan Schmidt,
- Carlos Barreto,
- Melanie Bird,
- Kristen Blann,
- Kelly Bona,
- Allison Cassidy,
- John Connolly,
- Scott J. Davidson,
- Lee Fedorchuk,
- Michelle Garneau,
- Lorna Harris,
- Hongxing He,
- Sarah Howie,
- Adam Kirkwood,
- Nicholas Pontone,
- Karen Richardson,
- Nicole Sanderson,
- Gilles Seutin,
- Bin Xu, and
- Xiangbo Yin
Knowledge and data on the current function, future threats, and benefits of peatlands in Canada are required to support evidence-based decision-making to ensure they continue to provide critical ecosystem services. This is particularly relevant for Canada, given the large expanse of relatively intact peatland area. There is a need, not only to standardize protocols, but also to prioritize types of information and knowledge that can best meet conservation and management goals. This was the challenge posed to the participants of the Global Peatlands Initiative workshop in June 2023 in Quebec City, Quebec, Canada. Participants were composed of researchers using primarily Western science approaches that use peatland data for carbon accounting, policy or sustainable land use, reclamation/restoration, conservation, wildlife, and water resources applications. For seven peatland data categories (hydrometeorological and environmental sensing; peat coring and depth; greenhouse gas monitoring; biodiversity; vegetation, woody debris, and litter; Traditional Knowledge; water quality), three priority measurements were identified and recommendations for their collection were discussed. The key recommendations from the workshop were to (1) create standardized, yet flexible protocols; (2) coordinate field data collection where possible; (3) weave more Traditional Knowledge into understanding of peatlands; (4) create an atlas of existing peatland information; (5) scope opportunities to create a network of peatland “super sites”. - OPEN ACCESS
- Mael Le Corre,
- Felipe Dargent,
- Vaughan Grimes,
- Joshua Wright,
- Steeve D. Côté,
- Megan S. Reich,
- Jean-Noël Candau,
- Marrissa Miller,
- Brent Holmes,
- Clement P. Bataille, and
- Kate Britton
Bioavailable strontium isotope ratios (87Sr/86Sr) distribution across the landscape mainly follow the underlying lithology, making 87Sr/86Sr baseline maps (isoscapes) powerful tools for provenance studies. 87Sr/86Sr has already been used in Eastern Canada (EC) to track food and human remains origins, or to reconstruct animal mobility. While bioavailable 87Sr/86Sr isoscapes for EC can be extrapolated from global datasets using random forest modelling (RF), no regionally calibrated isoscape exists. Here, we produce a regionally calibrated bioavailable 87Sr/86Sr isoscape by analysing plants collected at 136 sites across EC, incorporating updated geological variables and applying a novel ensemble machine learning (EML) framework. We generated and compared isoscapes generated by the traditional RF and the EML approaches. Adding local bioavailable 87Sr/86Sr to a global dataset significantly improved the model prediction with a drastic increase of predicted 87Sr/86Sr and increased spatial uncertainty in the northern Canadian craton. EML produced similar 87Sr/86Sr predictions but with tighter spatial uncertainty distribution. Regionally calibrated RF and EML isoscapes significantly outperformed the global bioavailable RF isoscape, confirming the requirement for collecting local data in data-poor regions. This isoscape provides a baseline in EC to monitor and manage the movements and provenance of agricultural products, natural resources, endangered/harmful migratory species, and archaeological human remains and artifacts. - OPEN ACCESS
- Jessie S. Reynolds,
- Chris K. Elvidge,
- Ian J. Vander Meulen,
- Caleb T. Hasler,
- Richard A. Frank,
- John V. Headley,
- L. Mark Hewitt, and
- Diane M. Orihel
We evaluated whether naphthenic acid fraction compounds (NAFCs) extracted from oil sand tailings adversely affect fish survival and behaviour. Following a before–after-control-impact design, we housed wild-caught juvenile yellow perch (Perca flavescens) in outdoor mesocosms to assess survival and behaviour under baseline conditions, then exposed fish to one of three treatments: negative control, 2 mg/L NAFC, or 15 mg/L NAFC. We performed behavioural assays (no-stimulus activity, food stimulus, and predator stimulus using a model bird) and assessed a comprehensive suite of endpoints (equilibrium losses, activity, shoaling, burst swimming, freezing, and space use). We found that exposure to 15 mg/L NAFCs substantially reduced fish survival and impaired fish equilibrium in all three behavioural tests. Furthermore, exposure to NAFCs impaired anti-predator behaviour: while the activity of control fish increased by two-fold in response to a predator stimulus, fish exposed to 2 or 15 mg/L NAFC did not change their activity levels after stimulation. No significant changes were observed in other behavioural endpoints. Overall, our findings suggest that a week-long exposure to NAFCs at concentrations commonly found in tailings ponds, constructed wetlands, and other mining-impacted waters may affect multiple facets of fish behaviour that could ultimately lead to reduced fitness in fish populations. - OPEN ACCESS
- Lesya Marushka,
- Xue Feng Hu,
- Tiff-Annie Kenny,
- Malek Batal,
- Karen Fediuk,
- Tonio Sadik,
- Christopher D. Golden,
- William W. L. Cheung,
- Anne K. Salomon, and
- Hing Man Chan
The objective of this study is to examine the potential cardiovascular risk of climate-related declines in seafood consumption among First Nations in British Columbia by assessing the combined effects of reduced omega-3 fatty acids and mercury intake from seafood on the risk of myocardial infarction (MI) in 2050 relative to 2009. The data were derived from the First Nations Food, Nutrition, and Environment Study. Seafood consumption among 369 randomly selected participants was estimated, and hair mercury concentrations were measured. Declines in seafood consumption were modelled based on previously projected climate change scenarios, and the associated changes in nutrients and contaminants were used to estimate the cardiovascular risk. Reduced seafood consumption was projected to increase the risk of MI by 4.5%–6.5% among older individuals (≥50 years), by 1.9%–2.6% in men, and by 1.3%–1.8% in women under lower and upper climate change scenarios, respectively. Reduced seafood consumption may have profound cardiovascular implications. Effective strategies are needed to promote sustainable seafood harvests and access to seafood for coastal First Nations. - OPEN ACCESS
- Ha Pham and
- Marc Saner
Inclusion has been gaining increased attention in various domains, including education and the workplace, as well as development, governance, urbanization, and innovation. However, in the context of climate change adaptation (CCA), the concept of “inclusiveness” remains comparatively underexplored, with no overarching framework available. This gap is crucial, given the global scope and multifaceted nature of climate change, which demands a comprehensive and inclusive approach. In this article, we address this deficiency by developing a comprehensive conceptualization of inclusive climate change adaptation (ICCA). Grounded in ethical analysis, our framework is presented for discussion and practical testing. We identify nine specific priority areas and propose one to two qualitative indicators for each, resulting in a suite of 15 indicators for the evaluation of ICCA policies. This research not only highlights the urgency of incorporating inclusiveness into CCA, but it also provides a practical framework by which to guide policymakers, practitioners, and researchers in this critical endeavor. By acknowledging and accommodating diverse value systems and considering the entire policy process, from conception to evaluation, we aim to foster a more inclusive and sustainable approach to CCA. - OPEN ACCESSDocumented plastic pollution throughout the Laurentian Great Lakes system prompted investigation of microplastics (MPs) in sediment cores. We examined offshore sediment cores from Lake Huron (LH43) and Lake Ontario (403A) to understand temporal trends and changes in microplastic (MP) pollution in the size range 53 µm to 2 mm. MP abundances varied from 18.1 to 280.1 particles per g of dry weight sediment (N g−1 dw) in LH43, and 8.2–488.4 g−1 dw in core 403A. The 15 cm cores are equivalent to 56 years of accumulation in Lake Huron and 72 years of accumulation in Lake Ontario. Analysis of the two cores shows an increasing trend in MP accumulation from 1964 to 1989, which mirrors the global plastic production rate. Subsequent peaks and troughs in the MP abundance profiles reflect macroeconomic changes and regional controls. These results show how changing abundances of MPs in lake sediment cores can act as proxies for global perturbations in oil supply as well as national economic shifts.
- OPEN ACCESSHistorical gold mining operations between the 1860s and 1940s have left substantial quantities of arsenic- and mercury-rich tailings near abandoned mines in remote and urban areas of Nova Scotia, Canada. Large amounts of materials from the tailings have entered the surface waters of downstream aquatic ecosystems at concentrations that present a risk to benthos. We used paleolimnological approaches to examine long-term trends in sedimentary metal(loid) concentrations, assess potential sediment toxicity, and determine if geochemical recovery has occurred at four lakes located downstream of three productive gold-mining districts. During the historical mining era, sedimentary total arsenic and mercury concentrations and enrichment factors increased substantially at all downstream lakes that received inputs from tailings. Similarly, chromium, lead, and zinc concentrations increased in the sediments after mining activities began and the urbanization that followed. The calculated probable effects of concentration quotients (PEC-Qs) for sediments exceeded the probable biological effects threshold (PEC-Q > 2) during the mining era. Although sedimentary metal(loid) concentrations have decreased for most elements in recent sediments, relatively higher PEC-Q and continued exceedance of Canadian Interim Sediment Quality Guidelines suggest that complete geochemical recovery has not occurred. It is likely that surface runoff from tailing fields, urbanization, and climate-mediated changes are impacting geochemical recovery trajectories.
- OPEN ACCESS
- D.T. Enright,
- P. Comeau, and
- D.M. Gillis
We used isodars, developed from the ideal free distribution (IFD), to predict the distribution of fishing effort across regulatory boundaries in the south-western Scotian Shelf’s haddock fishery. Our analysis was focused around the boundary between Northwest Atlantic Fisheries Organization’s Divisions 4X and 5Z. While effort within 4X was related to the standardized catch value and effort experienced along the 4X–5Z boundary, most effort predictions across the boundary were also accurate. Accuracy of these cross-boundary isodars suggests that a high degree of movement across the boundary meets the IFD assumption of free movement and thus, effort on one side of the boundary is related to fishing success on the other side of the boundary. Fisheries management strategies should adopt a broad view that encompasses adjacent regulatory regions to understand where vessels may choose to fish when multiple regulatory regions are accessible. In fisheries where isodars describe effort distributions across a regulatory boundary, the relative abundance of the underlying fish population could be better indicated by effort distribution among regulatory regions than by catch rates. - OPEN ACCESS
- John Chételat,
- Joel P. Heath,
- Lucassie Arragutainaq,
- John Lameboy,
- Christine McClelland, and
- Raymond Mickpegak
Spatial patterns of bioaccumulated mercury were evaluated in coastal marine food webs of east Hudson Bay and east James Bay in the boreal subarctic of Canada. Two marine species, blue mussels (Mytilus edulis) and common eider ducks (Somateria mollissima) that consume mussels, were collected by a regional community-based monitoring network established in five communities. Stable isotope tracers (carbon, nitrogen, sulfur, and mercury) were measured to evaluate environmental drivers of mercury spatial patterns. Mercury concentrations of blue mussels and common eiders were twofold and fivefold higher, respectively, on the James Bay coast near the community of Chisasibi compared to sites in east Hudson Bay. Liver and muscle mercury concentrations of eiders from James Bay are among the highest values reported for the circumpolar subarctic and Arctic. Multiple lines of evidence (mercury spatial patterns, crustal elements in blue mussels, and mercury isotope values of common eiders) suggest elevated mercury in the coastal food web of east James Bay may be due to mercury loading from the La Grande River, which drains one of the largest hydroelectric developments in the world. These findings highlight the importance of further research on environmental processes linking large rivers to mercury bioaccumulation in northern coastal food webs. - OPEN ACCESSMarine protected areas (MPAs) are critical in safeguarding biodiversity and ecosystem functions under climate change. The long-term effectiveness of these static conservation measures will depend on how well they represent current and future ocean changes. Here, we use the Climate Risk Index for Biodiversity to assess the vulnerability representation of marine ecosystems within the Canadian marine conservation network (CMCN) under two divergent emissions scenarios. We found that MPAs best represent climate vulnerability in Atlantic Canada (85% representativity overall, and 93% in the Gulf of Saint Lawrence under low emissions), followed by the Pacific (78%) and Arctic (63%; lowest in the Eastern Arctic (41% under high emissions) regions). Notably, MPAs with lower climate vulnerability are proportionally overrepresented in the CMCN. Broad-scale geographic targets employed in the Scotian Shelf-Bay of Fundy network planning process achieve over 90% representativity of climate vulnerabilities, underscoring the importance of ensuring habitat representativity and geographic distribution in conservation planning to enhance climate resilience, even if not explicitly prioritized. Moving towards Canada’s target to protect 30% of its waters by 2030, prioritizing representativity and designation of MPAs in currently underrepresented climate-vulnerable regions may be crucial to enhancing the resilience of the CMCN amidst an ever-changing climate.
- OPEN ACCESS
- Emily M. Rubidge,
- Carrie K. Robb,
- Patrick L. Thompson,
- Chris McDougall,
- Karin M. Bodtker,
- Katie S.P. Gale,
- Stephen Ban,
- Kil Hltaanuwaay Tayler Brown,
- Vicki Sahanatien,
- Sachiko Ouchi,
- Sarah K. Friesen,
- Natalie C. Ban,
- Karen L. Hunter,
- Angelica Pena,
- Amber Holdsworth, and
- Rebecca Martone
Marine protected area (MPAs) networks can buffer marine ecosystems from the impacts of climate change by allowing species to redistribute as conditions change and by reducing other stressors. There are, however, few examples where climate change has been considered in MPA network design. In this paper, we assess how climate change considerations were integrated into the design of a newly released MPA network in the Northern Shelf Bioregion in British Columbia, Canada, and then evaluate the resulting network against projected physical and biogeochemical changes and biological responses. We found that representation, replication, and size and spacing recommendations integrated into the design phase were met in most cases. Furthermore, despite varying degrees of projected changes in temperature, dissolved oxygen, and aragonite saturation across the MPA network, suitable habitat for demersal fish species is projected to remain in the network despite some redistribution among sites. We also found that mid-depth MPAs are particularly important for persistence, as fish are projected to move deeper to avoid warming in shallower areas. Our results highlight that a representative MPA network with adequate replication, that incorporates areas of varying climate change trajectory, should buffer against the impacts of climate change. - OPEN ACCESS
- Dylan Hillis,
- Kristina M. Barclay,
- Erin Foster,
- Hannah M. Kobluk,
- Taylor Vollman,
- Anne K. Salomon,
- Chris T. Darimont, and
- Iain McKechnie
Shellfish have supported Indigenous lifeways on the Pacific Coast of North America for millennia. Despite the ubiquity of clamshells in archaeological sites, shell size measurements are rarely reported due to a lack of applicable basis for generating size estimates from fragmentary remains. We present a linear regression-based method for determining shell length from hinge and umbo measurements of littleneck (Leukoma staminea; n = 239), butter (Saxidomus gigantea; n = 274), and horse (Tresus nuttallii; n = 92) clams using both contemporary and archaeological shells collected from three regions in coastal British Columbia, Canada. We examine the accuracy of these size estimations, which indicate that 83%–97% of the variability in dorsal shell length is predicted by umbo thickness and hinge length. Hinge length generated higher R2 values yet exhibited greater intra- and inter-observer error. While the predicted dorsal length for each species differed by region, this size difference was smaller than intra- and inter-observer error, suggesting broad applicability for these simple measurements. We applied these formulae to a Tseshaht First Nation archaeological clamshell assemblage (n = 488) on western Vancouver Island spanning 3000 years and observed profiles that resemble contemporary legal size limits, which suggests the sustained use and maintenance of local shellfisheries. The accuracy of these regression models for determining shell length from fragments highlights the utility of this approach as a basis for assessing past shellfish management practices. - OPEN ACCESSShallow ponds can provide ideal conditions for production of greenhouse gases (GHGs) carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O), and thus are important to include in global and regional GHG budgets. The Canadian Prairie Pothole Region contains millions of shallow natural ponds, and we investigated GHG dynamics in 145 ponds across the region. Ponds were consistently supersaturated with CH4, often supersaturated with CO2 (57% occurrence), and often undersaturated with N2O (65% occurrence). Spring measurements showed higher N2O saturation (p = 0.0037) than summer, while summer had higher CH4 (p < 0.001) and CO2 (p = 0.023) saturation than spring. Ponds exhibited large physicochemical variation, yet sulfate concentration and pH were strong predictors of dissolved CH4 and CO2, respectively. No predictor was identified for N2O. The link between sulfate and CH4 has important implications as dissolved CH4 in low sulfate (<178 mg L−1) systems was much more responsive to changes in temperature. This research fills an important knowledge gap about the GHG dynamics of prairie pothole ponds and the role of water chemistry for diffuse GHG release. Our work can also be used in ongoing efforts to describe ecosystem services (or disservices) assigned to ponds in this agriculture-dominated region.